title: Expression of J chain RNA in cell lines representing different stages of B lymphocyte differentiation.
abstract: During B cell differentiation to pentamer IgM secretion, synthesis of the pentamer joining component, the J chain, is initiated. We investigated the mechanism for initiating J chain synthesis by analyzing murine cell lines representing different stages in B cell differentiation. The expression of functional J chain mRNA was evaluated by cell-free translation and specific immunoprecipitation of a J chain product. The expression of precursor mRNA was examined by hybridization with a J chain probe obtained by molecular cloning of cDNA. No J chain-specific RNA could be demonstrated in a lymphoma line representative of an undifferentiated B lymphocyte, but three species of J chain RNA were identified in hybrid cell lines representative of IgM-secreting plasma cells: a mature message of approximately 1.5 kb and two minor components of 2.5 and 0.92 kb. The encounter of a B cell with antigen or mitogen must therefore trigger events that effect either transcription of J chain sequences or their intranuclear stabilization.
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D002454:Cell Differentiation; D002460:Cell Line; D003001:Cloning, Molecular; D007144:Immunoglobulin J-Chains / Q000096:biosynthesis*; D007075:Immunoglobulin M / Q000096:biosynthesis; D051379:Mice; D009693:Nucleic Acid Hybridization; D010954:Plasmacytoma; D012333:RNA, Messenger / Q000378:metabolism*
chemical_list: D007144:Immunoglobulin J-Chains; D007075:Immunoglobulin M; D012333:RNA, Messenger